Effects of molecular mass of a priming resin on bond strength to dentin

This dissertation analyzed one of the factors that enhance the strength of the bond to dentin of polymeric composite restorative materials. It was hypothesized that increasing the molecular mass of the primer would increase the strength of the bond between tooth and composite restorative material. The objective of the research was to synthesize an oligomer with similar side groups and to vary the molecular mass of this oligomer. The first step in this project was the synthesis of a novel oligomer for use as a primer (initial polymeric component applied to the tooth to enhance bonding). The oligomer synthesized can be altered by increasing the molecular mass or by changing the number of side groups that are attached to the oligomer. The general reaction involves two steps. The reaction is the copolymerization of maleic anhydride and tert-butyl methacrylate. The second step is the addition of 2-hydroxyethyl methacrylate across the anhydride ring.; The effects of molecular mass of the primer were examined by changing the number of units that are polymerized before the primer is placed on the tooth. The relative (to polystyrene standards) molecular masses of 886, 998, 3366, 4556 and 5862 were tested in a standard dentin bonding test (shear). There was not a statistically significant difference (p ≤ 0.05) between the two larger molecular masses and there was no statistically significant difference between the samples with mean molarcular mass of 886 and 3366 (p ≤ 0.05). There was a statistically significant difference between the all other pairwise comparisons (p < 0.05).